This invention relates to injection molding and more particularly to a multi-cavity injection molding system with a number of heated nozzles having pointed tips fixed to a common manifold. The manifold and nozzles are actuated between a retracted open position and a closed position in which each of the nozzle tips is seated in a gate to provide valve gating.
Heated nozzles are well known in the injection molding art. However, they are normally seated in a well in the cavity plate and fixed to the manifold, and neither the nozzles or the manifold moves. Valve gating is also well known in the injection molding art, but is it normally provided by a valve pin which extends through a central bore in each nozzle into the gate. One example of this type of system is shown in the applicant's Canadian patent application Ser. No. 524,969 entitled "Mechanism for Valve Gated Injection Molding with Resilient Retaining Ring" which was filed Dec. 10, 1986. While this arrangement is satisfactory for many applications, it has the disadvantage that separate actuating mechanisms are required for each valve pin of the multi-cavity system.
More recently, as described in the applicant's U.S. Pat. No. 4,669,971 entitled "Valve Gated Probe" which issued June 2, 1987, a system has been provided in which a number of probes having melt channels extending towards a tip end are valve gated simultaneously by actuating the common manifold. Nozzles having pointed tips are also known, as shown in the applicant's U.S. Pat. No. 4,557,685 entitled "Heated Nozzle for Injection Molding Apparatus" which issued Dec. 10, 1985. New fixed nozzles having a pointed tip and a sealing and locating flange are shown in the applicant's Canadian patent application Ser. Nos. 086,621 entitled "Coated Injection Molding Nozzle and Method" filed Aug. 18, 1987 and 087,044 entitled "Injection Molding Nozzle with Hollow Sealing and Locating Flange and Method" filed Aug. 19, 1987.